|  | 4.5 | Layer 3 Design
| 4.5.5 | Diagramming a standards-based LAN that uses routers
The Figure shows an example of an implementation that has multiple physical networks. All data traffic from Network 1 destined for Network 2 has to go through the router. In this implementation, there are two broadcast domains. The two networks have unique Layer 3 IP addressing network/subnetwork addressing schemes. In a structured Layer 1 wiring scheme, multiple physical networks are easy to create simply by patching the horizontal cabling and vertical cabling into the appropriate Layer 2 switch using patch cables. As we will see in future chapters, this implementation provides for robust security implementation. In addition, the router is the central point in the LAN for traffic destination.